Traffic light socket means



July 7, 1970 I G. slKLos 1 TRAFFIC LIGHT SOCKET MEANS Filed Oct. 18, 1967 2 Sheets-Sheet 1 July 7, 1970 s os 3,519,813

; TRAFFIC LIGHT SOCKET MEANS Filed Oct. 18. 1967 I 2 Sheets-Sheet 2 FIG.4

FIG.3

United States Patent O 3,519,813 TRAFFIC LIGHT SOCKET MEANS Gregory Siklos, Bronx, N.Y., assignor to The Marbelite Company, Inc., Brooklyn, N.Y. Filed Oct. 18, 1967, Ser. No. 676,190 Int. Cl. F21v 7/06 US. Cl. 240--41.35 12 Claims ABSTRACT OF THE DISCLOSURE An electrical socket construction for the mounting of an electric traffic signal bulb with the bulb being retained in a preselected position. The socket enables helical threading of a C-shaped filament bulb into a socket so that the opened portion of the C filament faces downwardly in a traflic signal whereby light output is maximized. Preferably, the socket construction is an integral part of a plastic housing and integral with a plastic reflector for a traflic signal bulb to minimize cost, maintenance and assembly operations.

BACKGROUND OF THE INVENTION Trafiic signal bulbs which have C-shaped filaments with the C lying in a plane perpendicular to the long axis of the bulb are commonly used in the traffic signal art. As is well-known, the bulbs are normally mounted in sockets with the long axes of the bulbs being horizontal. It is preferred to rotate the bulbs in conventional sockets until the C turns to a position where the opening of the C faces downwardly to maximize light output available to pedestrians and automobilists viewing the signals. However, in conventional sockets, when such a bulb is screw threaded, because of manufacturing tolerances necessarily used for both the sockets and the bulbs, often the bulb is only in a tightly held position when the opening of the C-shaped filament is in a position other than facing directly downwardly thus causing loss of efficiency in light output available to a viewer.

The art has sought to overcome such problems by the use of complex structures. Often socket arrangements comprise housings which are mounted in separate metallic reflectors and are rotatable in a plane perpendicular to the axis of such reflectors. A separate ring structure is used so that when one screws a traflic light bulb into the socket, the entire socket and bulb can then be rotated and fixed in position by a separate element such as a bail or alignment wire to achieve maximum usable light by facing the opening of the C downwardly in a traflic signal. Such structures have many parts including glass, bailing or alignment wires and rings, gasket means between separate sockets and reflectors and the like. The use of a plurality of separate elements, results in high production costs and loss of time in adjustment of the bulbs to their proper position as by adjustment of the bailing or alignment wire in traflic signals.

SUMMARY OF THE INVENTION According to the invention, a traflic signal has a bulb socket construction for mounting an electric bulb such as a C-shaped filament electric bulb to permit the opening of the C to be positioned downwardly in accordance with preferred procedure. An insulating housing carries a center contact for engagement with one lead of the bulb and a second contact for engagement with a second lead of the bulb. One of the contacts is fixed with respect to movement along a predetermined linear path which preferably comprises the long axis of the socket and the other of the contacts is movable along that path against the bias of a spring means. The other contact is 3,519,813 Patented July 7, 1970 positioned to move along the path when actuated by re tation of the bulb in the socket about a central axis of the socket in a helical thread. Preferably, the movable socket comprises a conductive socket member defining a helical groove or thread as is known in the art to engage with the helical thread on one contact of the electric bulb.

In the preferred embodiment, a socket housing of plastic carries contacts for an electric traflic signal bulb and has a plastic reflector molded integrally with the socket housing to form a one-piece unit of low cost. Preferably, all elements other than electrically conductive elements and spring elements of such an arrangement in a traflic signal are made of plastic.

The advantages of this invention include low cost production and ease of adjustment of a C-shaped filament to maximize usable light output in a trafiic signal light. Thus, a conventional threaded C-shaped filament bulb can be screwed into the socket of this invention and rotated about a helical path moving inwardly toward the socket along a central axis thereof until the center contact of the bulb meets a fixed center contact of the socket whereupon the bulb stops its linear movement but continues to rotate about the axis moving the socket or second contact outwardly from the socket until the C- shaped opening faces downwardly. At that point, rotation of the bulb is stopped and the spring bias maintains the bulb firmly in the socket.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will be better understood from the following specification when read in connection with the accompanying drawings in which:

FIG. 1 is a side perspective view with parts broken away of a preferred embodiment of this invention;

FIG. 2 is a front view thereof taken along line 2-2 of FIG. 1;

FIG. 3 is a cross sectional view taken along line 33 of FIG. 2; and

FIG. 4 is a semi-diagrammatic side view of an alternate embodiment thereof.

BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS With reference now to the drawings and more particularly FIG. 1, a traffic signal arrangement 10 is shown comprising a socket construction 11, a C-shaped filament bulb 12, a parabolic reflector 13. Preferably the socket construction comprises a socket housing 15 (FIG. 3) integrally molded of a plastic along with the reflector 13 to form a single piece construction. However, the particular socket arrangement of this invention is useful with metallic or other reflectors as well as with integral reflectors as described in the preferred embodiment.

Preferably the plastic of the housing 15 is a thermosetting plastic such as phenol formaldehyde although other thermosetting plastics can be used as can thermoplastic materials as is known in the art. In some cases when the socket housing is separate from the reflector, it can be of other materials than plastic or for example, porcelain.

The plastic socket housing 15 (FIG. 3) carries a tubular conductive socket member acting as a contact 16 as is generally known in the art. Contact 16 is threaded with helical grooves 17 having a central axis coaxial with the central axis of a central electrical contact 18. Inwardly turned flaps 19 and 20 of the contact 16 are mounted on the housing 15 by means of rivets 21 and 22 respectively. The rivets are fixed. at the inner ends to the plastic housing and have coaxial coil springs 23 and 24 passing between heads of the rivets and the flaps 19 and 20 as best shown in FIG. 3. From this figure, it will be seen that socket contact 16 can be pulled along a path outwardly of the socket housing or to the left as shown in FIG. 3, with the springs 23 and 24 being compressed and thus resiliently urging the contact 16 back toward the transverse wall 25 of the socket housing.

A plastic lining tube 26 can be employed as of polytetrafluoroethylene to enhance sliding action of the tubular socket member 16 within the tubular housing 15. In some embodiments, this lining can be eliminated.

The transverse wall 25 defines an air opening 27 and a passageway for a conventional headed screw 18 acting as a second contact along the central axis of the socket. Screw 18 has a contact button head 28 and is fixed in position by lock nuts 29 and 30 as is known in the art. The central contact 18 can be any conventional fixed contact member which is firmly mounted in the plastic housing and prevented from movement along its axis.

The reflector 13 can have an inner surface which can be metallized in accordance with known metallizing procedures to provide a good reflecting surface. In some cases, polishing and/or coloring of the plastic material used is sufficient to provide desired reflecting properties.

Suitable electrical connection can be made to a power supply through rivets 21 and/ or 22 and the rear end of contact 18 as when the entire assembly 10 is placed within a larger traflic casing which carries a lens in front of surface 14. The integral rims 40 and tabs 30 and 31 are used for mounting the assembly in traflic casings.

In assembly of the bulb with the socket, the bulb 12 is threadably engaged with threads 17 through the peripheral helically threaded lead of the bulb and rotated to move the bulb along its axis inwardly until the tip or central lead 42 of the bulb meets and abuts the tip of contact button lead 28 preventing further inward movement of the bulb. At this point, it may still be desirable to continue rotation of the bulb in order to have the opening 43 of the C-shaped filament pointing downwardly when the bulb is in the horizontal position shown in FIG. 1. Preferably the C-shaped filament lies in a plane perpendicular to the central axis of the socket contact 16. Thus, continued rotation is permitted while the socket member 16 is pulled in the direction of arrow against the resilient bias of springs 23 and 24 until the C-shaped opening is in the position shown in FIG. 1. At that point, the bulb is firmly mounted in the socket and will not be loose since the bias of the springs pull the socket along with the central contact or lead 42 of the bulb rearwardly into firm engagement with the head 28. It is important that the head 28 define the rearmost point of passage of the central contact 42 of the bulb since it is not only important that the C-shaped filament face downwardly, but, also important that the filament itself be located at a predetermined focal point of the parabolic reflector 13 to maximize light reflection within the reflector arrangement.

While a specific embodiment of this invention has been shown and described, it should be understood that many variations thereof are possible. For example, in FIG. 4, a variation of the spring bias arrangement is shown where bulb 12 is mounted against a fixed central contact 51 and tension springs 52 and 53 connect the contact 16 to the housing 54. In this embodiment, when the bulb is turned, the central axis will abut the center contact 51 and the housing be pulled outwardly against the spring bias of springs 52 and 53 until proper location in a predetermined position of the C-shaped filament is obtained.

Other modifications of the present invention are also possible. The particular spring arrangement can vary greatly depending upon specific design requirements. The design and mounting of the contacts may vary as can the shape of the socket housing 15. The socket housing 15 can be separate from the reflector with clamping rings or other means used to mount the reflector on the socket housing. Thus conventional metal reflectors can be used with the socket arrangement of this invention. Similarly, the specific design of the integral reflector and socket housing can be changed to meet particular requirements of a traflic signal. While it is preferred to design both the reflector and the socket for use with conventional Amplex-type C-shaped filament bulbs as for example 67- watt volt rated bulbs, various types of bulb arrangements can be used.

In View of the many modifications possible, this invention is to be limited only by the spirit and scope of the appended claims.

What is claimed is:

1. A socket construction for mounting an electric traflic signal bulb comprising, an insulating housing,

a center first contact for engagement with one lead of said bulb,

a second contact for engagement with a second lead of said bulb,

said center contact being fixed with respect to movement along a predetermined linear path and said second contact being movable along said path against the bias of a spring means,

said second contact comprising a tubular, conductive socket member defining a helical groove dimensioned to receive a peripheral lead of said bulb in threadable engagement therewith with said bulb having an axis aligned with a central axis of said second contact,

said second contact being positioned to move along said path when actuated by rotation of said bulb in said socket member about a central axis thereof in said helical thread.

2. A socket construction in accordance with claim 1 wherein said socket member is spring mounted in said housing in a first position.

3. A socket construction in accordance with claim 2 wherein said spring means comprises at least one coil spring having a central axis parallel to said second contact axis whereby rotation of said bulb to thread it in said second contact causes movement of said second contact away from said housing in said path when said bulb abuts said first contact so that rotation of said bulb can be accomplished to position a filament of said bulb in a predetermined position with respect to said socket construction with said bulb being retained in said predetermined position and urged against said first contact by said spring.

4. A socket construction in accordance with claim 3 wherein said spring means comprises two coil springs in compression mounted on either side of said central contact,

5. A socket construction in accordance with claim 1 and further comprising a reflector extending from said insulating housing and defining a focal point, said bulb having a C-shaped filament lying in a plane perpendicular to said central axis and being firmly mounted with said filament located at said focal point with said C-shaped filament facing in a predetermined direction.

6. A socket construction in accordance with claim 5 wherein said insulating housing and said reflector are plastic and integral.

7. A socket construction in accordance with claim 1 and further comprising a plastic reflector integral with said insulating housing.

8. A socket construction in accordance with claim 1 wherein said spring means is a tension spring means and said second contact is interconnected with said spring means for movement along said path.

9. A socket construction in accordance with claim 1 wherein a lining tube separates said socket member from said housing to enhance sliding action of said socket member.

10. A socket construction in accordance with claim 1 wherein said housing defines a cylindrical wall closely surrounding said tubular socket member, and a rear wall mounting said center contact.

11. A socket construction for mounting an electric trafiic signal bulb comprising,

a housing,

a center contact for engagement with one lead of said bulb,

a second contact for engagement with a second lead of said bulb, said second contact defining a helical thread,

said second contact being mounted on spring means,

said substantially central contact defining a central axis,

means for stopping movement of said traffic signal bulb at one predetermined point on said central axis,

said last-mentioned means acting in conjunction with said spring means for permitting movement of said second contact along said axis and simultaneous rotational movement of said bulb when said bulb is stopped from movement along said axis whereby said bulb can be easily mounted in said socket construction in a predetermined position.

12. A socket construction in accordance with claim 11 wherein said housing is plastic and an integral plastic reflector extends outwardly of said housing.

References Cited UNITED STATES PATENTS OTHER REFERENCES German application number 1,092,324, Nov. 3, 1960,

Germany, Rau.

NORTON ANSHER, Primary Examiner 20 R. L. MOSES, Assistant Examiner U.S. Cl. X.R. 

